This invention relates to a sliding member for use in an internal combustion engine and more particularly to a sliding member in which the sliding surface is produced by alloy spraying.
Sliding members for use in an internal combustion engine are subject to severe working conditions as typified by the relative sliding movement between a piston ring and a cylinder. Various proposals have been made in order to produce sliding members capable of use under severe working conditions. For example, molybdenum or molybdenum alloy spraying has been proposed as disclosed in U.S. Pat. Nos. 2,905,512 and 3,412,198. However, molybdenum spraying has serious drawbacks in that bonding between molybdenum particles is weak so that molybdenum particles have a tendency to drop off or to become separated from the resultant sprayed layer resulting in abrasive wear during operation. Further, since molybdenum is an expensive material such techniques are quite costly.
In order to overcome these difficulties, spraying of a mixture of metal and carbide has been proposed as disclosed in U.S. Pat. Nos. 3,539,192, 3,606,359, 3,615,099, 3,617,349, 3,620,137, 3,749,559 and 3,809,546. According to the disclosures of these patents, a mixture of tungsten carbide having an extremely high hardness and nickel is sprayed. The sprayed layer thus provided has an extremely high hardness so that this technique has several drawbacks in terms of machinability and production cost. Further, high energy is required to spray tungsten carbide, so that low productivity results.